The invention relates to a device for changing the position of a functional element in an electrical apparatus, in particular the head mounting plate in a magnetic-tape apparatus, the functional element being electromechanically movable between a rest position, towards which it is spring-loaded, and two spaced-apart operating positions, i.e. a first and a second operating position, which functional element is electromagnetically held in the first operating position by an electromagnet device and, when it leaves said first operating position due to the electromagnet device being de-energised, can be held in the second operating position with the aid of the mechanical holding function provided by a mechanical holding device.
In magnetic-tape apparatuses intended for playing back tape cassettes, in particular Compact Cassettes, it is known to move the magnetic head relative to the magnetic tape inside the cassette. For this purpose the magnetic head is arranged on a head mounting plate which is electromechanically movable. In a rest position of the head-mounting plate the magnetic head is fully withdrawn from the tape; in a first operating position of the head-mounting plate the magnetic head is fully positioned against the tape, referred to as the play position, and in an intermediate position between the first operating position and the rest position the magnetic tape can be moved past the head substantially without any contact. This position is referred to as the cue or MSS-position.
From DE-AS 29 10 243 it is known to hold the head-mounting plate in the rest position by means of a spring. If the head-mounting plate is to be set to the first operating position, an electromagnet is energized to draw the head mounting plate into the first operating position via a lever mechanism. The head-mounting plate can return from this first operating position to the rest position via a latching device at the location of the second operating position if the first magnet is de-energized and, in addition, the latching device is released by a second electromagnet. If the second electromagnet does not release the latching device the head-mounting plate remains in the second operating position for the time being.